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Biomedical subjects

N Oren

Publications and source records attributed to N Oren.

7 recordsLinked to original sources
PubMed2001

Bcl-2 and p53 expression in insular and in well-differentiated thyroid carcinomas with an insular pattern.

Expression of p53 and bcl-2 oncogenes was investigated in poorly differentiated, so-called insular carcinomas of the thyroid gland and also in the follicular and papillary carcinomas with an insular component. Hematoxylin-eosin sections of 217 thyroid carcinomas were reevaluated for insular carcinoma and also for thyroid carcinomas with an insular component. Immunohistochemical staining method was used for detecting p53 and bcl-2 expression on paraffin blocks of three pure insular, five follicular or papillary thyroid carcinomas with a major insular component (more than 50%) and six with a minor insular component (20-50%). Flow cytometry was also performed in these cases. None of the cases showed p53 immunoreactivity. Bcl-2 expression was observed in all cases and the most intense staining was seen in insular areas. All the cases were diploid. We suggest that bcl-2 plays a role in loss of differentiation of thyroid carcinomas.

Adult↗
PubMed2000

Epithelial membrane antigen and S-100 protein expression in benign and malignant papillary thyroid neoplasms.

Papillary carcinoma of the thyroid is mainly diagnosed with histopathologic features. Classical papillary architectures are important but nuclear change is the essential diagnostic element. Papillary architecture may be seen in benign lesions such as in hyperplastic areas of the follicular neoplasms, multinodular goiter and Grave's disease. Differential diagnosis of papillary carcinoma and papillary hyperplasia is very important for clinical management. Some authors have reported that Epithelial Membrane Antigen (EMA) and S-100 protein expression would be valuable and helpful in identifying papillary neoplasia and distinguishing it from papillary hyperplasia. In this study, EMA and S-100 protein expression of 14 papillary thyroid carcinomas and 13 papillary hyperplasias were studied by using immunohistochemical methods. In 14 papillary carcinomas, 9 showed diffuse and 3 revealed focal S-100 protein nuclear and cytoplasmic immunostaining. Two cases were not stained. All of the 13 papillary hyperplasias were negative for S-100 protein. EMA expression was observed in the apical cytoplasmic location of 11 papillary carcinomas except one case that showed diffuse cytoplasmic staining and one which was negative. In the papillary hyperplasias, 7 revealed both cytoplasmic and apical cytoplasmic staining. One case showed only cytoplasmic staining. Five cases were negative for EMA. The difference in the S-100 protein expression is significant, however immunostaining of EMA is similar in both lesions. We concluded that differential diagnosis of papillary structures in carcinomas and hyperplasias was mainly diagnosed on the histopathologic features but S-100 protein expression could be helpful in difficult cases.

Carcinoma, Papillary↗
PubMed1991

Motor nerve terminal staining combined with catecholamine histofluorescence or immunocytochemistry.

A number of excellent techniques are available to stain and characterize different types of neurons and nerve terminals. However, because these different techniques are frequently not compatible, their usefulness in determining the relationships between specific axons and neuromuscular junctions is often limited. The goal was to develop specific procedures for simultaneous visualization of different types of unmyelinated axons and motor nerve terminals in the same preparation. First we modified the formaldehyde/glutaraldehyde staining solutions of the aqueous aldehyde fluorescence technique (Faglu) to observe catecholamine containing axons in whole mount amphibian skeletal muscle. The compatibility of this modified staining solution with other histological procedures made it possible to stain both motor nerve terminals with tetrazolium salts and, in the same preparation, to observe unmyelinated axons with aldehyde-induced catecholamine histofluorescence. This same general formaldehyde/glutaraldehyde staining procedure was also used with immunocytochemical techniques to visualize fluorescent antibody stained nerves and motor nerve terminals in the same whole mount preparation.

Acetylcholinesterase↗
PubMed1989

Presence of alpha-melanocyte-stimulating hormone-like immunoreactivity in the innervation of amphibian skeletal muscle.

Amphibian motor nerve terminals are sensitive to a wide variety of peptides, including alpha-melanocyte-stimulating hormone (alpha-MSH). We determined the presence and distribution of alpha-MSH-like immunoreactivity (alpha-MSHLI) in the innervation of the cutaneous pectoris muscle from bullfrog (Rana catesbeiana) tadpoles and postmetamorphic froglets, and adult frogs (R. catesbeiana and R. pipiens). alpha-MSHLI was found in unmyelinated, noncholinergic axons, in motor axons, and in motor nerve terminals. In motor axons, alpha-MSHLI was predominantly associated with neurofilaments. The distribution of this form of alpha-MSHLI changed during development and seasonally in adult frogs. The possible functional roles of this alpha-MSHLI are discussed.

Aging↗